Huge following in Social networking sites like face book, Twitter, Google +, LinkedIn etc will help you to reach out to more number of potential buyers. Keep your Social Networking pages highly active by conducting contests, polls etc. This will make you gain more followers.
It is not necessary that the followers of your Social Networking Page to become your buyers. But they can spread out word of mouth to their friends and family about your products and services, who may be interested in buying. This process goes on like a chain reaction and helps you to reap in more buyers.